DC & Exchange loses connection during VEEAM Backup

June 25, 2020 at 1:01 pm Leave a comment

Problem:

Outlook users get disconnected periodically (at the same time everyday).

When we analyzed the situation, we found out that the issue coincides with the backup windows. Further, investigation reveals that it happens exactly at the time of VMware snapshot removal stage, and this is quite normal ,since the VM will experience a longer VM stun.(Can be confirmed by looking in to the vmware.log). This was causing the VM (Domain Controller) to freeze, and at this time the Exchange triggers a Netlogon error with the eventID 5719 because it loses the connection to the domain controller. The outlook users (Desktop & Smartphone) will be forced to re-open the email client or re-enter the credentials.

Solution:

So to avoid this , we had to convert the backup job from VM based to an Agent based. The agent based backup uses the VSS instead of VMware API triggered VM based snapshots.

Once the above is changed , we did not see any Netlogon event ID 5719 appeared and the users did not complain thereafter.

Good Luck